Not worth it imo. I'm still getting ristretto's that can only be beat by the local roaster here. There 100 other cafes don't really compare. I only dare order an espresso at one other place, which is drinkable but kinda bland. I'm just trying to expand my abilities. If the grinder really is the issue then i'll just save up and get one down the track.

I'm assuming that pump pressure isn't the issue then considering no one has touched on it?

Ran a blind basket with the pump on for 25 seconds and measured the over pressure volume of water. Got 109ml. This would lead me to believe that the pump is in fact running slightly over pressure, yes?

Try updosing. From what I learned, early blonding is the act of which the puck has exhausted it's extraction. I may be wrong. But I believe upping your dosage might the early blonding problem.

Logically speaking, increasing the dosage = more for water to extract = puck being "less exhausted". I'm not an expert of this, but just suggestion from my knowledge. Let me know how it goes!

Also, the "sourness" of the espresso usually is an indication of under extraction. I'm actually a bit confused also....early blonding = exhausted puck, yet the sourness usually means under extraction.